server: Change zlib compression level (#47387)

close #47278
pingcap · Oct 3, 2023 · ddee0a5 · ddee0a5
1 parent 95378e5
commit ddee0a5
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Showing 2 changed files with 4 additions and 3 deletions.
diff --git a/server/internal/packetio.go b/server/internal/packetio.go
@@ -381,12 +381,13 @@ func (cw *compressedWriter) Flush() error {
 	// https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_basic_compression_packet.html
 	// suggests a MIN_COMPRESS_LENGTH of 50.
 	minCompressLength := 50
+	zlibCompressDefaultLevel := 6
 	data := cw.buf.Bytes()
 	cw.buf.Reset()
 
 	switch cw.compressionAlgorithm {
 	case mysql.CompressionZlib:
-		w, err = zlib.NewWriterLevel(&payload, zlib.HuffmanOnly)
+		w, err = zlib.NewWriterLevel(&payload, zlibCompressDefaultLevel)
 	case mysql.CompressionZstd:
 		w, err = zstd.NewWriter(&payload, zstd.WithEncoderLevel(cw.zstdLevel))
 	default:

diff --git a/server/internal/packetio_test.go b/server/internal/packetio_test.go
@@ -242,10 +242,10 @@ func TestCompressedWriterLong(t *testing.T) {
 		cw.Flush()
 
 		// Header:
-		// 3c 00 00   Compressed length: 60
+		// 18 00 00   Compressed length: 24
 		// 00         Packetnr: 0
 		// 45 00 00   Uncompressed length: 69
-		compressedLength := []byte{0x3c, 0x0, 0x0}
+		compressedLength := []byte{0x18, 0x0, 0x0}
 		packetNr := []byte{0x0}
 		uncompressedLength := []byte{0x45, 0x0, 0x0}
 		require.Equal(t, compressedLength, testdata.Bytes()[:3])